Spears, 24, married Federline, 28, in 2004. They have a 1-year-old son, Sean Preston, and an infant son, Jayden James, who was born Sept. 12.

A message left with Spears' attorney, Laura Wasser, was not immediately returned.

Spears married Federline eight months after ending a 55-hour Las Vegas marriage to her childhood friend, Jason Alexander (no relation to the actor of the same name). Her second marriage has provided endless fodder for tabloids, which have speculated frequently that the union was in trouble.

"There is no statement at this time as requested by Mark's client, Kevin Federline," said Michael Sands, a spokesman for Kaplan.

In the divorce papers, Spears asks for custody of the couple's two children, with visitation rights for Federline. The filing lists as separate property, and thereby off-limits to Federline, "miscellaneous jewelry and other personal effects," earnings and other assets to be determined later.

The filing came a day after Spears, back in shape after the birth of her second child, made a surprise appearance on David Letterman's "Late Show" in New York City by popping up behind him as he was sitting at his desk.

Federline appeared in the movie "You Got Served" and performed as a backup dancer for singer Justin Timberlake, Spears' former boyfriend. He previously was involved with actress Shar Jackson of TV's "Moesha." Federline and Jackson have two children.

Born in Kentwood, La., in 1981, Spears got her first taste of fame at age 11 when she joined the "New Mickey Mouse Club" TV show. Her fellow Mouseketeers included Timberlake, Christina Aguilera, Ryan Gosling and Keri Russell.

Five years after leaving the show she released her debut album, "Baby One More Time." In the video for the title track, Spears dressed provocatively in a school uniform and cemented her reputation as a sex symbol. Yet, throughout a years-long romance with Timberlake, Spears always proclaimed her chastity.

By 2003, she had fully embraced her sex-charged image, sharing an open-mouthed kiss with Madonna during the MTV Video Music Awards.